Screening and sizing process and apparatus



May 22, 1.923.,

1,455,785 C, HACKSTAFF SCREENING AND SIZING PROCESS AND APPARATUS Filed De c. 18,1193) 2 Sheets-Sheet 1 INVEN TOR.

Geo.

May 22,1923. 1,455,785

GQ C. HACKSTAFF SCREENING AND SIZING PROCESS AND APPARATUS Filed Dec. 18, 1920 2 Sheets-Sheet 2 Patented May 22, 1923.

unites stares GEORGE C. HACKSTAFF, OF DENVER, COLORADO.

SCREENING AND SIZING PROCESS AND APPARATUS.

Application filed December 18, 1920.

To all whom it may concern.

Be it known that I, Gnonon C. HACK- STAFF, a citizen of the United States, residing at the city and county of Denver and State of Colorado, have invented certain new and useful Improvements in Screening and Sizing Processes and Apparatus; and

I do declare the following to be a full, clear,

and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

The object of this invention is to provide means for quickly and efficiently screening and sizing materials.

The invention comprises a screen adapted to receive the material, said screen preferably being arranged in sections of diflerent mesh for the purpose of sizing or grading the material as it moves along the screen, an arm or shaft being connected with the middle portion of each section and operable by a magnet controlled by make-and-break mechanism, whereby the screen is rapidly vibrated or pulsated in a direction perpendicular to the plane of the screen.

In the drawings:

Fig. 1 is a plan of the invention;

Fig. 2 is a view partially in vertical section and partially in elevation;

Fig. 3 is an elevational detail showing the connection of the magnet and shaft with the screen;

Fig. 4; is a side elevation of the generator with the make-and-break mechanism; and

Fig. 5 is an end elevation thereof.

Cross timbers 10 are mounted upon a substructure 12 and carry sections of screen 14. An upper railing or framework 16 is provided around the screen and carries thereon a plurality of cross bars 18, one of such bars being provided for each screen section 14.

Each bar 18 carries a wall break-magnet 20 which is bolted thereto, and a vertically disposed shaft or arm 22, which is pivoted at its upper end as indicated at 24 to the magnet and which is secured to the central portion of the screen 14 by being passed therethrough. Preferably, washers 25 of rubber are disposed on the opposite sides of the screen and are bound in position by means of securing nuts 26. Conductors 28 Serial No. 431,748.

and 30 are connected with the magnets, conductor 28 being grounded on the generator 82, and the other conductor 30 beingsecured to an insulated arm 33 on the generator and in electrical connection with a brush 34 also carried by said arm, said brush 34 being in engagement with a make-and-break roller 35 of known type mounted on the armature shaft 36. When the generator 32 is in operation, the current is alternately made and broken by the brush 34 and roller 35 at a rate varying with the speed of the generator. In actual practice this is preferably about 3,000 times a minute. This causes the magnets 20 to be energized at the same speed, whereby the shaft 22 is lifted and dropped at the same rate, which causes a rapid vibration or pulsation to be imparted to the screen 14: at its middle portion. This pulsation produces highly efficient screening in that it causes the small particles to be positively forced through the screen at a high speed.

The screen is inclined slightly so as to' have a drop of two or three inches in about ten or twelve feet. In this manner the material being screened travels along from one section to another, the gradually increasing sizes dropping through the successive screens into the respective hoppers 15 therebeneath.

The result is a product obtained in a variety of sizes in a very short interval of time, which renders the device much more efficient. than other types of screening apparatus heretofore known.

I claim:

1. A machine for screening powdered ore comprising a frame inclined about two inches in every twelve feet, a screen attached thereto, said screen comprising a plurality of sections of graduated mesh, a supporting member over each screen section, a magnet provided with a movable armature secured to said supporting member, means connecting said armature with the central portion of each screen section. and means for periodically energizing said electromagnet whereby the latter vibrates the screen in a direction substantially perpendicular to the plane of the screen.

2. A machine for screening powdered ore comprising a slightly inclined frame composed of a plurality of substantially rectangular sections, screens attached to each earner caries.

section and inclined about two inches in everyctwelve' feet,-"said "screen sections being of graduated mesh, 21 supporting member overeach screen section, an electromagnet having amovab'le-armature secured to said supporting member, means connecting each of said armatures Witha screen section, and

means for supplying said magnet with an interrupted electric current fir/hereby said armatures Will cause the "screen section to vibrate. i

In testimony 'WhQIGO-f I-aflix my signature.

GEORGE- o. HAOKSTAFF. 

